It is known that the site of ATP-synthesis in mitochondrial oxidative phosphorylation is the ATPase enzyme. The ATPase is normally membrane-bound, but may be obtained in a soluble form which retains the ability to rebind to the membrane and to reconstitute oxidative phosphorylation. In this proposed research, the binding sites on the ATPase will be investigated. We will document the number and binding- affinity of the various binding sites. We will attempt by affinity labelling and other modification methods to identify, locate and characterize these binding sites. Interaction of the enzyme with the mitochondrial inner membrane will also be investigated. This research should greatly enhance our understanding of the molecular events which occur on the enzyme, and in the membrane, during ATP synthesis.